Preferential involvement of 11q23-24 and 11p15 in breast cancer.

Thirty cases of breast cancer were cytogenetically studied by G-banding using direct tumor preparations. Among them 20 cases exhibited abnormalities of the long and/or short arm of chromosome 11. Thus, 11q was involved in 16 cases and 11p in ten cases. There was consistent involvement of bands 11q23-24 (15 cases) and 11p15 (9 cases), where the cellular oncogenes ets and H-ras 1, respectively, are located. These findings suggest that involvement of bands 11q23-24 and 11p15 may be specific in a group of breast cancers, leading to the activation of cellular oncogenes or loss of cancer suppressor genes.